COVID-19 Vaccine Effectiveness

Last updated 15th June 2021

Waning Vaccine Effectiveness – July 2021

Data from Israel’s health ministry suggests Pfizer’s Covid-19 vaccine is far less effective at preventing infection and symptomatic illness with the Delta variant than with previous strains of coronavirus.

A full course of the Pfizer-BioNTech vaccine was just 39% effective at preventing infections and 41% effective at preventing symptomatic infections caused by the Delta Covid-19 variant, according to Israel’s health ministry.

The vaccine still provides very high levels of protection against hospitalization (92%) and severe illness (91%) caused by the Delta variant, the ministry said.

In a statement, Pfizer and BioNTech noted that while real-world data from Israel show vaccine efficacy in preventing infection and symptomatic disease to decline six months post-vaccination.

Effectiveness of the Vaccines Against Symptomatic Disease – Before July 2021

The following evidence has been reported for the effectiveness of vaccines by Public Health England.

The figures show the effectiveness at stopping symptomatic disease two weeks after the second dose.

From Delta (Indian) Variant

Pfizer

Second Jab – 88%

AstraZeneca

Second Jab – 60%

From Alpha (UK – Kent) Variant

Pfizer

Second Jab – 93%

AstraZeneca

Second Jab – 66%

Effectiveness of the Vaccines Against Hospitalisation – Before July 2021

Data from Public Health England shows the the effectiveness of the vaccines against hospitalisation to be as follows.

From Delta (Indian) Variant

Pfizer

First Jab – 94%

Second Jab – 96%

AstraZeneca

First Jab – 71%

Second Jab – 92%

From Alpha (UK – Kent) Variant

Pfizer

First Jab – 83%

Second Jab – 95%

AstraZeneca

First Jab – 76%

Second Jab – 86%